This invention relates to filler neck caps, and particularly to a rotatable cap for closing the open mouth of a filler neck. More particularly, this invention relates to a filler neck cap engageable with internal flanges formed in the filler neck to cause the cap to be retained quickly and easily in the filler neck.
Conventional caps for closing the filler neck of a vehicle fuel tank typically include a closure member carrying a seal for closing and sealing the mouth of the filler neck and a handle for turning the closure member to mount the closure member and seal in the filler neck. A typical filler neck cap includes a ring-shaped seal made of a resilient gasket material that is compressed between the cap and a filler neck receiving the cap to establish a sealed connection between the cap and the filler neck when the cap is mounted on the filler neck.
Newly manufactured "O-ring" seals of the type used in filler neck caps meet certain stringent size, elasticity, and hardness (durometer) requirements. Over time, however, O-ring seals, as well as other seals, mounted in filler necks tend to shrink, become less elastic, and smaller in cross section due to "O-ring compression set" which occurs when an O-ring seal is exposed to a compression load over time. Such compression loading occurs whenever a cap carrying an O-ring seal is installed in a filler neck. Filler neck cap O-ring seals also degrade over time as a result of normal wear following repeated installations and removals of the cap on and from the filler neck.
According to the present invention, a cap is provided for a filler neck having an open mouth and an internal mounting flange adjacent to the open mouth. The cap comprises a handle, a body coupled to the handle for rotation therewith, an annular seal around the body, an external position-locator lug appended to the body and arranged to lie in spaced-apart relation to the annular seal, and a spiral-shaped cap mounting member appended to the body to lie in a position between the annular seal and the external position-locator lug. The spiral-shaped cap mounting member is adapted to engage against the internal mounting flange of the filler neck upon installation of the body in the filler neck to retain the cap in the filler neck.
In preferred embodiments, the spiral-shaped cap mounting member has a first end positioned to lie either adjacent to or in contact with the external position-locator lug. The external position-indicator lug includes an inclined flange guide. The spiral-shaped cap mounting member includes an annular cap retainer facing toward the handle and being adapted to engage against the internal mounting flange of the filler neck upon installation of the body in the filler neck. The annular cap retainer at the first end of the spiral-shaped cap mounting member is arranged to merge into the inclined flange guide on the position-locator lug.
The body of the cap has a cylindrical exterior surface. The spiral-shaped cap mounting member is appended to the cylindrical exterior surface. The spiral-shaped cap mounting member is formed to include a second end spaced apart from the first end and to have an arc length along the cylindrical exterior surface characterized by a central angle about one hundred sixty degrees. The body has a cylindrical exterior surface and the spiral-shaped cap mounting member is oriented to wind helically around the cylindrical exterior surface.
The filler neck has an outer end including a cylindrical interior side wall and first and second filler neck mounting flanges appended to the cylindrical interior side wall and arranged to define first and second lug-receiving spaces therebetween. The cap preferably includes a cylindrical body that is sized to fit into the outer end of the filler neck and first and second position-locator lugs that are appended to the cylindrical body and arranged to lie in spaced-apart relation to one another so that each position-indicator lug is situated to pass through one of the lug-receiving spaces defined between the first and second filler neck mounting flanges during an initial stage of cap installation in the filler neck. The annular seal is positioned to lie around the cylindrical body and engage a flange appended to the cylindrical body and an annular outer rim included in the outer end of the filler neck during cap installation in the filler neck. First and second spiral-shaped cap mounting members are appended to the cylindrical body and positioned to lie between the overlying annular seal and the underlying position-locator lugs and arranged to engage the first and second filler neck mounting flanges to retain the cap in an installed position in the filler neck and compress the annular seal between the flange appended to the cylindrical body and the annular outer rim included in the filler neck.
Additional features and advantages of the invention will become apparent to those skilled in the art upon consideration of the following detailed description of preferred embodiments exemplifying the best mode of carrying out the invention as presently perceived.